Seven years ago, while trying to create a sandwich based on the principles of a cheese plate at his restaurant the Foundry, Eric Greenspan came up with a combination of walnut raisin bread, taleggio cheese, apricot caper compote, arugula and short ribs. It went on to win the Grilled Cheese Invitational. And now, four years after he first mentioned the idea, Greenspan’s Grilled Cheese finally opened in April in a small space next to the building that had housed the Foundry.